Piper Comanche PA-24 Service Manual page 718

PIPER COMANCHE SERVICE MANUAL
317
G".OUND
,
.,.
SPRING
S
BATTERY
0
'-----'GIA~OU;:lN~D:_::~==\\;:.;:;!J~~TACHOMEi'
STARTING MOTOA
aATTl!RY
h:::;:h<iGIAOUND
1
GAOUND
STARTlNG MOTOR
FIGURE 9-29 •. Nc)'L.OAD TEST HOOKUP FIGURE 9·291. STAL.L.·TOIIQUE HOOKUP
play sbould be .005 to .050 of an iIIcb.
b. New brushes should be properly seated
"he.
,:wtaIUIl&by "rappin& a strip of 00 sandpaper
ar",,1Id the cammutator (with the sandilll side OI1t) 1.25 to 1.50 tilll •• Maximum. Drop brusbes on
sandpaper coverod Ctlllfllutator and tum the .....
tuN
slowly in the direction
of
rotation. Dust
sbould be blown out of the motor after sandina.
NOTE
Tbe spring tension is 32 to 40 ouaces with new brusb ••. This ten-
sion is measured with the scale hooked under the brush sprine
near
the brusb and the :eadiog is taken
It
right angies to the line of
force exerted by the brush spring.
c. Check the position of the plnioo to be sure the unit .,ilI.mesh properly with the flywheel
ring gear. See spec ifieations for wut fex correct dimensions. Refer to paralraph 9-90.
9-88. aench T ..
t._
a. After the starting motor is reassembled,
it
sbould be tested to see that the no-load current
at a certain YoLta,e is within specificatials as &iven in
parasrapb g...90. To make this test
I
con-
neet .s shown
in
Ficure 9-2ge. U current is too higb. check the bearing ali&Mlent and e,d play
to make sure there is no bindine or interferencer. Two or three sbarp raps on
the
frame with a raw-
hide hammer ... ill often help to alien the !leanap and free the armature.
b. If no difficulty is indicated
in the above test, a stall torque test may be made to see if
the startinl motor is producine its rated. crankinc power. M:ake test connectiena as shown in
Figure 9-29f.
c. If torque and cunent .. e not within specifications. check the seatine of the brushes and
intemal conneaions [or hich resistance. If these cbecks are !Dade and found to be in IOod. order.
replace frame and field assembly and retest starter.
EL.ECTRICAL. SYSTEM
ISSUED: 8/18172
3
C18